Dual-zone heater for plasma processing

ABSTRACT

A method and apparatus for a pedestal is provided. In one embodiment, the pedestal includes a body comprising a ceramic material having a flange, one or more heating elements embedded in the body, a first shaft coupled to the flange, and a second shaft coupled to the first shaft; wherein the second shaft includes a plurality of fluid channels formed therein that terminate in the second shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/009,345, filed Jan. 28, 2016, which application claims priority toU.S. Provisional Patent Application Ser. No. 62/113,941, filed on Feb.9, 2015, which are hereby incorporated by reference herein.

BACKGROUND Field

Embodiments disclosed herein generally relate to a semiconductorprocessing chamber and, more specifically, a heated support pedestal fora semiconductor processing chamber having multi-zone temperaturecontrol.

Description of the Related Art

Semiconductor processing involves a number of different chemical andphysical processes enabling minute integrated circuits to be created ona substrate. Layers of materials which make up the integrated circuitare created by chemical vapor deposition, physical vapor deposition,epitaxial growth, and the like. Some of the layers of material arepatterned using photoresist masks and wet or dry etching techniques. Thesubstrate utilized to form integrated circuits may be silicon, galliumarsenide, indium phosphide, glass, or other appropriate material.

In the manufacture of integrated circuits, plasma processes are oftenused for deposition or etching of various material layers. Plasmaprocessing offers many advantages over thermal processing. For example,plasma enhanced chemical vapor deposition (PECVD) allows depositionprocesses to be performed at lower temperatures and at higher depositionrates than achievable in analogous thermal processes. Thus, PECVD isadvantageous for integrated circuit fabrication with stringent thermalbudgets, such as for very large scale or ultra-large scale integratedcircuit (VLSI or ULSI) device fabrication.

The processing chambers used in these processes typically include asubstrate support or pedestal disposed therein to support the substrateduring processing. In some processes, the pedestal may include anembedded heater adapted to control the temperature of the substrateand/or provide elevated temperatures that may be used in the process.Conventionally, the pedestals may be made of a ceramic material, whichgenerally provide desirable device fabrication results.

However, ceramic pedestals create numerous challenges. One of thesechallenges is multiple zone heating and/or accurate temperature controlof the pedestal and substrate during processing.

Therefore, what is needed is a pedestal that is temperature-controlledin multiple zones.

SUMMARY

A method and apparatus for a heated pedestal is provided. In oneembodiment, the pedestal includes a body comprising a ceramic materialhaving a flange, one or more heating elements embedded in the body, afirst shaft coupled to the flange, and a second shaft coupled to thefirst shaft; wherein the second shaft includes a plurality of fluidchannels formed therein that terminate in the second shaft.

In another embodiment, a pedestal for a semiconductor processing chamberis provided. The pedestal includes a body comprising a ceramic material,a plurality of heating elements encapsulated within the body, a firstshaft coupled to the body, and a second shaft coupled to the firstshaft; wherein the second shaft includes a plurality of fluid channelsformed therein, at least a portion of the fluid channels terminating inthe second shaft.

In another embodiment, a pedestal for a semiconductor processing chamberis provided. The pedestal includes a body comprising a ceramic material,a plurality of heating elements encapsulated within the body, a firstshaft coupled to the body, and a second shaft coupled to the firstshaft; wherein the second shaft includes a plurality of fluid channelsformed therein, at least a portion of the fluid channels terminating inthe second shaft, and wherein the first shaft is made of a firstmaterial and the second shaft is made of a second material that isdifferent than the first material.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to embodiments, someof which are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only typical embodimentsand are therefore not to be considered limiting of its scope, for theembodiments disclosed herein may admit to other equally effectiveembodiments.

FIG. 1 is a partial cross-sectional view of one embodiment of a plasmasystem.

FIG. 2 is a schematic cross-sectional view of one embodiment of apedestal that may be utilized in the plasma system of FIG. 1.

FIG. 3A is a schematic cross-sectional view of another embodiment of apedestal that may be utilized in the plasma system of FIG. 1.

FIGS. 3B-3D are cross-sectional views of alternative embodiments of afirst shaft of the pedestal of FIG. 3A.

FIG. 4A is a schematic cross-sectional view of another embodiment of apedestal that may be utilized in the plasma system of FIG. 1.

FIG. 4B is a partial side cross-sectional view of the pedestal shown inFIG. 4A.

FIG. 4C is a plan view of one embodiment of a coolant channel.

FIG. 5 is a schematic cross-sectional view of another embodiment of apedestal that may be utilized in the plasma system of FIG. 1.

FIG. 6 is a schematic cross-sectional view of another embodiment of apedestal that may be utilized in the plasma system of FIG. 1.

FIG. 7 is a schematic cross-sectional view of one embodiment of aportion of a pedestal that may be utilized in the plasma system of FIG.1.

FIG. 8A is schematic cross-sectional view of another embodiment of aportion of a pedestal that may be utilized in the plasma system of FIG.1.

FIG. 8B is schematic cross-sectional view of another embodiment of aportion of a pedestal that may be utilized in the plasma system of FIG.1.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Embodiments of the present disclosure are illustratively described belowin reference to plasma chambers, although embodiments described hereinmay be utilized in other chamber types and in multiple processes. In oneembodiment, the plasma chamber is utilized in a plasma enhanced chemicalvapor deposition (PECVD) system. Examples of PECVD systems that may beadapted to benefit from the disclosure include a PRODUCER® SE CVDsystem, a PRODUCER® GT™ CVD system or a DXZ® CVD system, all of whichare commercially available from Applied Materials, Inc., Santa Clara,Calif. The Producer® SE CVD system chamber (e.g., 200 mm or 300 mm) hastwo isolated processing regions that may be used to deposit thin filmson substrates, such as conductive films, oxide films such as siliconoxide films, carbon-doped silicon oxides and other materials. Althoughthe exemplary embodiment includes two processing regions, it iscontemplated that embodiments disclosed herein may be used to advantagein systems having a single processing region or more than two processingregions. It is also contemplated that embodiments disclosed herein maybe utilized to advantage in other plasma chambers, including etchchambers, ion implantation chambers, plasma treatment chambers, and inresist stripping chambers, among others. It is further contemplated thatembodiments disclosed herein may be utilized to advantage in plasmaprocessing chambers available from other manufacturers.

FIG. 1 is a partial cross-sectional view of a plasma system 100. Theplasma system 100 generally comprises a processing chamber body 102having sidewalls 112, a bottom wall 116 and a shared interior sidewall101 defining a pair of processing regions 120A and 120B. Each of theprocessing regions 120A, 120B is similarly configured, and for the sakeof brevity, only components in the processing region 120B will bedescribed.

A pedestal 128 is disposed in the processing region 120B through apassage 122 formed in the bottom wall 116 in the system 100. Thepedestal 128 provides a heater adapted to support a substrate (notshown) on the upper surface thereof. The pedestal 128 may includeheating elements, for example resistive heating elements, to heat andcontrol the substrate temperature at a desired process temperature.Alternatively, the pedestal 128 may be heated by a remote heatingelement, such as a lamp assembly.

The pedestal 128 is coupled by a flange 133 to a stem 126. The stem 126couples the pedestal 128 to a power outlet or power box 103. The powerbox 103 may include a drive system that controls the elevation andmovement of the pedestal 128 within the processing region 120B. The stem126 also contains electrical power interfaces to provide electricalpower to the pedestal 128. The power box 103 also includes interfacesfor electrical power and temperature indicators, such as a thermocoupleinterface. The stem 126 also includes one or more coolant channels 151.The stem 126 also includes a base assembly 129 adapted to detachablycouple to the power box 103 thereto. The coolant channels 151 may extendto the pedestal 128, terminate within the stem 126, or combinationsthereof. A circumferential ring 135 is shown above the power box 103. Inone embodiment, the circumferential ring 135 is a shoulder adapted as amechanical stop or land configured to provide a mechanical interfacebetween the base assembly 129 and the upper surface of the power box103.

A rod 130 is disposed through a passage 124 formed in the bottom wall116 of the processing region 120B and is utilized to position substratelift pins 161 disposed through the pedestal 128. The rod 130 is coupledto a lift plate 131 that contacts the lift pins 161. The substrate liftpins 161 selectively space the substrate from the pedestal to facilitateexchange of the substrate with a robot (not shown) utilized fortransferring the substrate into and out of the processing region 120Bthrough a substrate transfer port 160.

A chamber lid 104 is coupled to a top portion of the chamber body 102.The lid 104 accommodates one or more gas distribution systems 108coupled thereto. The gas distribution system 108 includes a gas inletpassage 140 which delivers reactant and cleaning gases through ashowerhead assembly 142 into the processing region 120B. The showerheadassembly 142 includes an annular base plate 148 having a blocker plate144 disposed intermediate to a faceplate 146. A radio frequency (RF)source 165 is coupled to the showerhead assembly 142. The RF source 165powers the showerhead assembly 142 to facilitate generation of a plasmabetween the faceplate 146 of the showerhead assembly 142 and the heatedpedestal 128. In one embodiment, the RF source 165 may be a highfrequency radio frequency (HFRF) power source, such as a 13.56 MHz RFgenerator. In another embodiment, RF source 165 may include a HFRF powersource and a low frequency radio frequency (LFRF) power source, such asa 300 kHz RF generator. Alternatively, the RF source may be coupled toother portions of the processing chamber body 102, such as the pedestal128, to facilitate plasma generation. A dielectric isolator 158 isdisposed between the lid 104 and showerhead assembly 142 to preventconducting RF power to the lid 104. A shadow ring 106 may be disposed onthe periphery of the pedestal 128 that engages the substrate at adesired elevation of the pedestal 128.

Optionally, a cooling channel 147 is formed in the annular base plate148 of the gas distribution system 108 to cool the annular base plate148 during operation. A heat transfer fluid, such as water, ethyleneglycol, a gas, or the like, may be circulated through the coolingchannel 147 such that the base plate 148 is maintained at a predefinedtemperature.

A chamber liner assembly 127 is disposed within the processing region120B in very close proximity to the sidewalls 101, 112 of the chamberbody 102 to prevent exposure of the sidewalls 101, 112 to the processingenvironment within the processing region 120B. The liner assembly 127includes a circumferential pumping cavity 125 that is coupled to apumping system 164 configured to exhaust gases and byproducts from theprocessing region 120B and control the pressure within the processingregion 120B. A plurality of exhaust ports 132 may be formed on thechamber liner assembly 127. The exhaust ports 132 are configured toallow the flow of gases from the processing region 120B to thecircumferential pumping cavity 125 in a manner that promotes processingwithin the system 100.

Embodiments of the disclosure provide method and apparatus to design atemperature-controlled zone ceramic heater (i.e., the pedestal 128 asdescribed herein) and control thereof to achieve ultimate temperatureuniformity and real-time temperature tuning capability in RF plasmaenvironments. The configurations of the coolant channels 151, describedin more detail below, enables temperature control of the pedestal 128.The pedestal 128 is not limited to use in CVD/PECVD processing chamberand may be used in PVD and etch semiconductor processing chambers.

Conventional heaters have limited cooling capability that cannot controlthe heater temperature with high RF power condition. The heat loss fromconventional heaters is not enough to compensate the heat provided by RFplasma when controlling the heater temperature at about 260 degreesCelsius, and above. Meanwhile, in a conventional dual zone heater, onlyone thermocouple is enclosed in the center of ceramic heater. The outerzone heater temperature is calculated by measuring outer zone heatingelements. A required specific power is provided to the heater in orderto obtain a heating element resistance and then achieve an appropriatetemperature resolution. This power will raise the temperature of theheater, although the heater is required to stay cool during plasmaprocessing. Furthermore, the configuration of an RF mesh, serving as aground plate or plate electrode in the heater, affects RF coupling of asubstrate. The RF coupling in conventional heaters, especially in theregion of the mesh where the lift pin holes are located, is limited.

FIG. 2 is a schematic cross-sectional view of one embodiment of apedestal 200 that may be utilized as the pedestal 128 in the plasmasystem 100 of FIG. 1. The pedestal 200 includes a heater body 205coupled to a stem 126. The heater body 205 includes a heating element210 embedded inside the heater body 205. The heater body 205 maycomprise a ceramic material, such as an aluminum nitride material, orother ceramic material. The stem 126 in this embodiment is a two-pieceassembly and includes a first shaft 215 coupled to a flange 133, and asecond shaft 220 coupled to the first shaft 215. The first shaft 215 andthe second shaft 220 may be made of different materials that conductheat away from the heater body 205. For example, the first shaft 215 maybe made of a material having a first thermal conductivity property thatis different than a second thermal conductivity property of the materialof the second shaft 220. The first shaft 215 may be made of aluminumnitride and the second shaft may be made of aluminum. The first shaft215 may be diffusion bonded to the heater body 205, for example,diffusion bonded to the flange 133.

In some plasma processes performed in the plasma system 100 of FIG. 1,the temperature of the pedestal 200 during plasma processing is about260 degrees Celsius. The pedestal 200 may be heated by a combination ofpower provided to the heating element 210 embedded inside the heaterbody 205 as well as heat obtained from plasma during a process in theprocessing regions 120A and 120B of FIG. 1. In many cases, thetemperature of the heater body 205 cannot be maintained and may elevateto a temperature above about 260 degrees Celsius.

As shown in FIG. 2, a coolant 230, such as ethylene glycol mixed withwater, a GALDEN® fluid, or a gas, is flowed through the second shaft 220in order to reduce the temperature of the heater body 205. Alternativelyor additionally, a length of the first shaft 215 may be shortened toposition the second shaft 220 closer to the heater body 205, which mayimprove the cooling capability. The coolant may flow in a hollowportion, such as a conduit 235, which may be one of the coolant channels151 shown and described in FIG. 1, of the second shaft 220.

FIG. 3A is a schematic cross-sectional view of another embodiment of apedestal 300 that may be utilized as the pedestal 128 in the plasmasystem 100 of FIG. 1. The pedestal 300 may be an alternative oradditional aspect to the pedestal 200 shown in FIG. 2. According to thisembodiment, the design of first shaft 215 may be adapted to increasethermal conduction. For example, a thickness T of a wall 305 of thefirst shaft 215 may be increased from about 0.1 inches up to about 0.4inches as compared to the first shaft 215 in FIG. 2. Increasing thethickness T of the wall 305 may be used to increase thermal flux fromthe heater body 205 to the second shaft 220. Alternatively oradditionally, an interface 310 where the first shaft 215 and the secondshaft 220 are coupled, may be configured to have increased surface area(e.g., an increased thickness and/or cross-section) to further increasethermal conduction of the stem 126. An interface 315, where the firstshaft 215 and the flange 133 are coupled, may also be configured to havean increased surface area (e.g., an increased thickness and/orcross-section) to maximize conduction of heat away from the heater body205. The increased surface area may include increasing thecross-sectional area of both of the first shaft 215 and the second shaft220, and may also simplify the shaft design as well as improve themechanical connection at the interfaces 310 and/or 315. A coolantchannel, such as a conduit 235, is also shown in the second shaft 220.The conduit 235 may be in fluid communication with a heat exchanger. Theheat exchanger may be chilled to improve heat removal from a fluidflowing in the conduit 235.

FIGS. 3B-3D are cross-sections of alternative embodiments of the firstshaft 215 where a height H may be varied alone or in combination withthe thickness T of the wall 305. Variations in the height H of the firstshaft 215 may be used to increase thermal flux from the heater body 205to the second shaft 220. Additionally or alternatively, the shape of theinterface 315 may be varied to increase thermal conduction and/orincrease thermal flux from the heater body 205 to the second shaft 220.

FIG. 4A is a schematic cross-sectional view of another embodiment of apedestal 400 that may be utilized as the pedestal 128 in the plasmasystem 100 of FIG. 1. In this embodiment, the pedestal 400 includes anactive coolant feed, using a liquid or a gas, as a coolant 230. Thepedestal 400 as described and shown in FIGS. 4A-4C features a closedloop active water cooling or gas feed which removes heat from the heaterbody 205 and/or on a substrate (not shown). The cooling of pedestal 400can be dramatically improved by directly flowing a coolant 230 into alower portion 402 of the heater body 205. One or more flow channels 420may be formed in side walls of the first shaft 215 and the second shaft220, and flowed to a coolant channel 425, which may be one of thecoolant channels 151 shown and described in FIG. 1, formed in the heaterbody 205. In some embodiments, the heater body 205 may include a firstplate 405 and a second plate 410 that are bonded together. The coolantchannel 425 may be formed in one or both of the first plate 405 and thesecond plate 410. The plates 405, 410 may be joined by diffusionbonding. A flange 133 of the pedestal 400, where the first shaft 215couples to the heater body 205, may also include a shoulder 415. Theshoulder 415 includes a dimension 430 (e.g., a diameter) that is greaterthan a dimension 435 (e.g., a diameter) of the first shaft 215. Theshoulder 415 may be used to increase conduction of heat away from theheater body 205 which may reduce cold spots in the heater body 205.

FIG. 4B is a partial side cross-sectional view of the pedestal 400 shownin FIG. 4A showing an alternate location of the coolant channel 425 thatis embedded in the heater body 205. The coolant channel 425 according tothis embodiment is positioned at an interface 440 of the first plate 405and the second plate 410.

FIG. 4C is a plan view of one embodiment of the coolant channel 425 thatis embedded in the heater body 205. The coolant channel 425 includes asubstantially circular fluid path having an inlet 445 and an outlet 450.A sidewall 455 of the first shaft 215 (shown in FIG. 4A) is shown inphantom near a center of the coolant channel 425. The inlet 445 and theoutlet 450 are substantially aligned with the sidewall 455 such that theone or more flow channels 420 (shown in FIG. 4A) may be in communicationtherewith.

FIG. 5 is a schematic cross-sectional view of another embodiment of apedestal 500 that may be utilized as the pedestal 128 in the plasmasystem 100 of FIG. 1. In this embodiment, the pedestal 500 includesbackside cooling and chucking capability. The pedestal 500 includes oneor both of an inner gas channel 520 and an outer gas channel 525 incommunication with a coolant 230. The inner gas channel 520 and theouter gas channel 525 may comprise the coolant channels 151 shown anddescribed in FIG. 1. Other gas channels may be included. The inner gaschannel 520 may be used to provide a cooling gas to a center region ofthe heater body 205 to cool a substrate 501. The outer gas channel 525may be used to provide a cooling gas to an edge of the heater body 205to cool an edge of the substrate 501. The cooling gas comprising thecoolant 230 may be helium, argon or nitrogen, or combinations thereof,among other gases. The inner gas channel 520 and the outer gas channel525 may be formed in the sidewall of the first shaft 215 and the secondshaft 220 and each may form a closed loop fluid line. The inner gaschannel 520 and the outer gas channel 525 may be formed to allow gas toleak to the vacuum chamber (e.g., the processing regions 120A and 120Bof FIG. 1) around the edge of the substrate 501. One or more channels505 may be formed in or on one or both of the first plate 405 and thesecond plate 410 of the heater body 205. The pedestal 500 provideshighly flexible temperature tunability of the substrate 501 duringprocessing in order to actively control the substrate temperature usinga single or dual gas feed. The dual zone backside gas configurationprovided by the inner gas channel 520 and the outer gas channel 525provides an efficient node for center to edge temperature tunability ofthe substrate 501.

The pedestal 500 may also include a RF mesh 510 which serves a chuckingelectrode. Small holes formed in the first plate 405 may be used toallow gas leakage to a top surface 515 of the heater body 205. Theelectrostatic chuck also allows gas to pass between the substrate 501and the top surface 515 and leak about the edge of the substrate 501.

FIG. 6 is a schematic cross-sectional view of another embodiment of apedestal 600 that may be utilized as the pedestal 128 in the plasmasystem 100 of FIG. 1. In this embodiment, the lift pins 161 (only one isshown) have a shaft 602 with minimal diameter D as compared toconventional lift pins. The minimized diameter of the shaft 602 of thelift pin 161 provides for a smaller (lesser diameter) lift pin guide 605in the heater body 205. The minimized size of the lift pin guide 605provides an opening 610 formed in the RF mesh 510 to be smaller thanopenings in RF mesh in conventional pedestals. The minimized opening 610provides enhanced RF coupling, especially in the area of the lift pins.In one embodiment, the diameter D is less than about 0.01 inches.

FIG. 7 is a schematic cross-sectional view of one embodiment of aportion of a pedestal 700 that may be utilized as the pedestal 128 inthe plasma system 100 of FIG. 1. The pedestal 700 includes a portion ofthe second shaft 220 coupled to a base assembly 129. The base assembly129 includes a tubular mating member 705 having an opening 710 thatreceives at least a portion of the second shaft 220 that is configuredas an insert 715. The tubular mating member 705 may be a sleeve that atleast partially surrounds the second shaft 220. In some embodiments, thetubular mating member 705 completely surrounds a peripheral surface ofthe second shaft 220. The tubular mating member 705 may be made ofaluminum.

In one embodiment, the insert 715 may be made of aluminum. The secondshaft 220 is sized slightly smaller than the opening 710 to providecontact between the insert 715 and the tubular mating member 705.According to this embodiment, the coolant inlet of the second shaft 220has a surface contact with a cooling base (e.g., the base assembly 129).O-rings 720 may be used to provide a seal between the base assembly 129and the second shaft 220. Connectors 725 of the fluid feed are locatedat the side of the base assembly 129, which reserves space for otherfeatures like terminals and filters (not shown). The insert 715 may alsoinclude a fluid channel 730 which may be one of the coolant channels 151shown and described in FIG. 1.

FIGS. 8A and 8B are schematic cross-sectional views of anotherembodiment of a portion of a pedestal 800 that may be utilized in theplasma system of FIG. 1. The second shaft 220 has surface contact with acooling base 805 adjacent to the sidewall of the second shaft 220.Additionally, the pedestal 800 includes the insert 715 which includes afluid channel 815 formed therein. In some embodiments, the tubularmating member 705 includes a fluid channel 730 formed in a side wallthereof similar to the embodiment of FIG. 7. The fluid channel 815 andthe fluid channel 730 may be the coolant channels 151 shown anddescribed in FIG. 1. Both of the fluid channel 730 and the fluid channel815 may be a closed loop fluid path (e.g., coupled to separate coolantsources (not shown)). Alternatively, both of the fluid channel 730 andthe fluid channel 815 may be coupled to a common coolant source (notshown).

FIG. 8B is an alternative embodiment of the pedestal 800 of FIG. 8A. Inthis embodiment, the fluid channel 815 formed in the insert 715 isfluidly coupled to a fluid channel 820 formed in the insert 715 adjacentto the base assembly 129.

Embodiments of a pedestal described herein provide a multi-zone heaterthat provides more efficient heat control as well as a wider range oftemperature tunability. Low temperature maintenance may also beenhanced, which increases the applicability of the pedestal to lowtemperature film formation processes.

While the foregoing is directed to embodiments of the disclosure, otherand further embodiments of the disclosure may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

The invention claimed is:
 1. A pedestal for a semiconductor processing chamber, comprising: a body comprising a ceramic material; a plurality of heating elements encapsulated within the body; a first shaft coupled to the body; and a second shaft coupled to the first shaft, wherein the second shaft includes a plurality of fluid channels formed therein, at least a portion of the fluid channels terminating in the second shaft, wherein the first shaft is made of a first material and the second shaft is made of a second material that is different than the first material, and wherein the plurality of fluid channels comprise a first set of fluid channels and the pedestal includes a second set of fluid channels formed in the first shaft and the second shaft.
 2. The pedestal of claim 1, wherein the second shaft is at least partially surrounded by a sleeve.
 3. The pedestal of claim 1, wherein one or more of the second set of fluid channels terminate in the body.
 4. The pedestal of claim 1, wherein an insert is disposed within the second shaft.
 5. The pedestal of claim 4, wherein the insert includes one or more fluid channels formed therein.
 6. The pedestal of claim 1, wherein the body includes an RF mesh and one or more lift pins movably disposed therethrough, each of the one or more lift pins having a diameter of about 0.01 inches, or less.
 7. A pedestal for a semiconductor processing chamber, comprising: a body comprising a ceramic material; a plurality of heating elements encapsulated within the body; a first shaft coupled to the body; and a second shaft coupled to the first shaft, wherein the second shaft includes a plurality of fluid channels formed therein, at least a portion of the fluid channels terminating in the second shaft and at least another portion of the fluid channels terminating in the body, and wherein the first shaft is made of a first material and the second shaft is made of a second material that is different than the first material, and wherein the plurality of fluid channels comprise a first set of fluid channels and the pedestal includes a second set of fluid channels formed in the first shaft and the second shaft.
 8. The pedestal of claim 7, wherein the second shaft is at least partially surrounded by a sleeve.
 9. The pedestal of claim 8, wherein the sleeve is coupled to a cooling base.
 10. The pedestal of claim 8, wherein the sleeve comprises a base assembly.
 11. The pedestal of claim 7, wherein the second shaft comprises an insert.
 12. The pedestal of claim 11, wherein the insert includes one or more fluid channels formed therein.
 13. The pedestal of claim 7, wherein the body includes one or more lift pins movably disposed therethrough, each of the one or more lift pins having a diameter of about 0.01 inches, or less.
 14. A pedestal for a semiconductor processing chamber, comprising: a body comprising a ceramic material; a plurality of heating elements encapsulated within the body; a first shaft coupled to the body; and a second shaft surrounded by a sleeve and coupled to the first shaft, wherein the second shaft includes a plurality of fluid channels formed therein, at least a portion of the fluid channels terminating in the second shaft, wherein the first shaft is made of a first material and the second shaft is made of a second material that is different than the first material, and wherein the plurality of fluid channels comprise a first set of fluid channels and the pedestal includes a second set of fluid channels formed in the first shaft and the second shaft.
 15. The pedestal of claim 14, wherein the sleeve is coupled to a cooling base.
 16. The pedestal of claim 14, wherein the sleeve comprises a base assembly.
 17. The pedestal of claim 14, wherein an insert is disposed within the second shaft.
 18. The pedestal of claim 17, wherein the insert includes one or more fluid channels formed therein. 